Mechanics of the normal and osteoarthritic hip. A new perspective.

The mechanism of force transmission in normal and osteoarthritic human hips is interpreted with the aid of the following hypothesis: the essential anatomic requisite for the maintenance of mechanical equilibrium about the hip is a horizontal acetabular weight-bearing surface. Anatomic deviations from this norm result in a disequilibrium of opposing vector forces and may be contributory to the eventual onset of osteoarthritis (OA). The radiographic anatomy of the hip is the temporal record of the biologic response of bone to load transmission. From the analysis of radiographs the magnitude and direction of mechanical forces about the hip can be inferred. Deviations from normal, as in OA, can be understood by such radiographic analyses.